Alloys of the noble metals such as gold and members of the platinum family possess outstanding resistance to all types of corrosion at or near body temperatures. This exceptional chemical stability is highly desirable in biological applications where it is essential to prevent soft tissue reactions and insure a high degree of reliability. It is felt that the use of alloy systems containing noble metals has been unusually limited partly due to their high cost but also because of a scarcity of basic information on their constitution and properties. Constitution diagrams for these alloy systems are of great use to metallurgists in designing new and improved alloys since these diagrams provide a graphic summary of the various phases existing in an alloy as a function of composition and temperature under equilibrium conditions. The studies being conducted in this research are directed toward exploring the constitution diagrams of the noble metals in binary combinations with other transition elements such as vanadium, chromium, niobium, etc. An effort is being made to systematize these data in order to reveal any trends in phase stability and to outline those composition regions which may be associated with outstanding physical and mechanical properties.